A large plate is fabricated from a steel alloy that has a plane strain fracture toughness of 55 MPa(m)1/2 If, during service use, the plate is exposed to a tensile stress of 200 MPa (29,000 psi), determine the minimum length of a surface crack that will lead to fracture. Assume a value of 1.0 for Y.

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Which one of the following faults cause the coffee in a brewer to keep boiling after the brewing cycle is finished? a. an open circuit in the heating element b. a short circuit at the terminals c. welded contacts on the thermostat d. a leak around the gasket

Two slings are used to lift a girder of length l and uniform weight per unit length. what is the best position for the slings if the bending moment due to the weight of the girder is to be kept to a minimum?